1. Field of the Invention
The present invention relates to a method for transmitting a message to a mobile station, which method comprises the steps of: storing a predetermined message in a memory means, and specifying a receiver for the message stored, the receiver consisting of one or more mobile stations. Furthermore, the invention relates to a mobile communication system comprising a mobile services switching centre, radio means having a data transmission connection to the mobile services switching centre for setting up a connection to mobile stations by radio signals, and memory means for storing a message designated for one or more mobile stations.
2. Description of the Related Art
In known mobile communication systems, such as the GSM system (Global System for Mobile Communications), short messages in the form of text can be transmitted to a subscriber, the system transmitting the messages to the receiver almost immediately after the sender has sent the message.
An object of the present invention is to improve the user-friendliness of known mobile communication systems and to provide a wider range of opportunities for the subscribers of a mobile communication system for transmitting messages to other subscribers of the system or to the subscribers themselves. This objective is achieved by the method of the invention, the method being characterized by comprising the steps of: specifying an area corresponding to the message stored, monitoring the location of the receiver specified for the message, and retrieving said message from the memory means and transmitting the message to the user of a receiving mobile station when the receiving mobile station arrives in said area.
The invention is based on the idea that the user-friendliness of the mobile communication system is dramatically improved when the subscribers are given the option of specifying a reception area for messages they have transmitted. In that case, a message designated for a receiver is not transmitted to the user of a receiving mobile station until a mobile station specified as the receiver of the message arrives in the reception area. This may take place either by the mobile communication system not transmitting the message to the receiving mobile station until the receiving mobile station arrives in the reception area or, alternatively, by the mobile communication system transmitting the message at an earlier stage to the receiving mobile station, when it arrives in the radio cell in which the reception area of the message is located, for example. The receiving mobile station then transmits the message it has received to the user by a user interface not until the mobile station has arrived in the reception area. The latter alternative is advantageous in that if a mobile station which comprises a GPS receiver is in question, for example, the mobile station does not need to transmit its location co-ordinates to other parts of the system, but it can itself monitor when its location co-ordinates correspond to the reception area co-ordinates included in the message it has received.
The invention enables the subscribers of a system to store reception-area-dependent messages which are transmitted to a receiver not until/if the receiver arrives in the reception area. This opens up totally new opportunities for the use of short messages, for example. In future, the short messages can be utilized in the following ways, for example:
at home, a wife leaves a short message in the doorway (reception area) for her husband""s mobile station, the short message reminding her husband to take his briefcase with him to work,
a message can be left for a personal mobile station at the parking place of a summer residence, the message including a request to check that the gas tap is closed and the door is locked,
a message can be left at a certain location in the Nuuksio outdoor recreation area, all mobile stations being specified as the receivers of the message, the message including information on the attractions at the location,
a message can be left for all mobile stations in the doorways of hospitals and airports, the message including a request to switch off the mobile phones, and
orienteerers are able to prove to have visited control points, i.e. the reception areas in which short messages are stored, by showing the short messages received by their mobile stations.
The location of a mobile station can be detected by using any solution. Naturally, the solution used for detecting the location then affects the accuracy with which the reception area can be specified. For example, if a mobile station having a GPS (Global Positioning System) or a corresponding electronic navigation device integrated thereto is in question, then the mobile station can be arranged to transmit location information at given intervals to other parts of the system in accordance with the invention, and the location detection of the mobile station can then be based on this information.
Alternatively, in the GSM system, for example, the location of a mobile station can be detected by utilizing timing advance assigned to it by a base station, the timing advance being directly proportional to the distance between the mobile station and the base station. The mobile station can be located by combining information on the timing advance with some other information, on the sector of the base station in which the mobile station is located, for example.
Furthermore, it is conceivable that a GSM mobile station, for example, can be located using measurement results it has reported. In other words, the mobile station of the GSM system informs, at given intervals, other parts of the system of the signal strength at which it receives the signals transmitted on a broadcast channel by the six base stations it receives best. The location of the base station can then be estimated on the basis of this information.
A mobile station can also be located on the basis of measuring the propagation delay of the signals the mobile station has received from the base stations. In other words, when the base stations are mutually synchronized to transmit signals at accurately defined moments of time, the location of the mobile station can be detected by measuring the time it takes for the mobile station to receive the signals of different base stations. The mobile station can be located by determining the propagation delay to several base stations.
The most significant advantages of the method of the invention include dramatically improved user-friendliness and a wider range of opportunities to transmit messages to other users of the system, providing entirely new opportunities for the use of short messages, for example.
In a preferred embodiment of the method of the invention, specifying the area corresponding to the message comprises the steps of: entering said area, storing the message in the memory means from said area by using a mobile station, and in connection with storing the message, storing in the memory means information indicating the location of the mobile station used. The embodiment of the invention enables the reception area to be specified in an extremely simple manner which does not require map co-ordinates to be fed, for example, or the use of other auxiliary devices together with the mobile station.
Furthermore, the invention relates to a mobile communication system to which the method of the invention can be applied. The mobile communication system of the invention is characterized in that the system comprises: means for storing in the memory means information indicating a reception area corresponding to the message stored in the memory means, monitor means for monitoring the location of at least one mobile station, for which mobile station a message is stored in the memory means, and transmitter means which are responsive to the monitor means for transmitting the message stored in the memory means to the mobile station monitored when said mobile station is located within the reception area corresponding to the message in question.
The preferred embodiments of the method and mobile communication system of the invention are disclosed in the attached dependent claims 2 to 5 and 7 and 8.